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Patented July 26, 7949 rem OFFICE 1 ANTIMALARIALs AND raocess or i MAKING Robert 0. Elderfield, rat

James D. Head, New

angsta Hudson, and York, N.

,assignors to the United States of America as represented by the Secretary of War Application erial No. 660,414

April are. it

\ *1 Claims. (siesta-seer h this invention r'elates t6 certain new antrmalarials and to the process of preparing them. The new antimalarials are 5,6-dimethoxy-8- substituted quinolinesrepresented by the following formula:

in Which R represents a-iriethyi or ethyl-substithtedtetrar peh'ta-metiiyle e radical, and R1 represents an alkylradicalhaving from lto '6 carbon atomsyand their salts. Thus, B may be a methyl -substitu'ted butyl radical such as l rnethylbutyl, an 'ethyl siibstitiited biiijyl {radical such as 4l-ethylbutyl, a methyl siibstitutedperityl radical such as l-methyl pgntyl, or an ethyl substituted pentyl radical. Examples oi the R1 d a il ud me rt: dim-jerseys .i f v and the several butyhp'enty n d'hexyl'r'adicals.

These new {substitutedfuuinolines have antirrialarial action which i'appea to be favorable i i'z m e 's nj. ti nj s in conjunction with quiriirleto 'haiie curative value in human Pl. vivax malaria.

The new substitutedaquinolines may be prepared .by condensing 5,6 dimethoxy 8-aminoquinolin'e with 'hydiohalide t an "alkyl'amino- 1, ari'dfiarpresents on fbrtii'ehaidens chlorine and bromine and is preferring, bromine. This condensation is desirably carried out by I h water two molecular proportions oi the allrylarriinoalkyl bromide hydrobromide w h n m lecul r snowmen of .fi-ii line, with sufficient disodium phosd buffer-topro i'de-apH of about 4.8. The mixture is held within a ;few degrees of l C. for 1 2 to 14-hours ,and the temperature is then progressively raised, and-finally held at about 95--l00f C.1 ior 5 to-6 hours. The mixture is then poured into'cold water and madealkaline, as with sodium or potassium hydroxide solution, which liberates as *a free base the desired 5,6- dimethoxy-8-substitutd quinoli "'e. This is separated by extraction with ether; and may be purifled by extracting theiether'solution with an aqueous acetic acid-sodium acetate buffer solution,

and recovering the desired sued-sate 'oiui'noline from the buffer solution I h The final ether solution is distilled in an "inert atmosphere at a pressur'e of-less than a temperature of about 225-250? 0., 'to yield the in purifiediorrn.

, The 5;6-dimethoxy-a substituted quinolines may be characterized in'the form oi their oxalates. It is noted that oxalic aciddoes not always unite in stoichiometric -ratio with the organic base, and that thecharacterization maybe carried out by determining the percentages of base and oxalic hydrogen figures from these values. The 5,6? dimethoxy-S-substituted quinoline bases are somewhat unstable, and are desirably converted phosphates, the ci-trates, etc.

The 5,6-dimethoxy ii-aminoquinoline used in the condensation described above may be pre- A. Williamson, described in the publication: Elderfield, Gensler, Williamson, "et -al., J. Chem. soc, 68, 1584 (1946-), and also the co- Serial No. 660,412, filed April 8,1946, entitled Method for producing a basic compound.

The following are examples of the invention:

5,6 dimethoxy-8- (l'-methyl-4'-isopropylaminobutylamino) -quinoline represented by the following formula by making it alkalineand extracting with ether.

bout 0.5 mm. pressure and a bath desired free: 'base acid in the salts, and calculating the carbon and to their salts, for example the hydrohalides, the

pared by the method "ofio'ur co-work'er Thurmond pending application of Thurmond A. Williamson,

Example 1 (3 I nc \N HN CH O-Hi) FNH O H 0 m in, a

maybe prepared as follows: 4 A y i 1 methyllisopropylaminobutyl bromide ghydrobromide used in this example, and certain other hydrobromides correspondingly used in Examples 4, '5, 6, '7, are described by :Elderfield i and Brody, in-their copendins application Serial No, 660,413, filed :April 8, '1946,now Patent No. 2,646,199; an in the paper of Elderfield .et at, =1J 1,A.; G.-S..68, 1519r1946) A- mixture of 57.8 g. '(0-.2*mol.) =of wl methylisopropylaminobutyl bromide hydrobromide, E30 m1. of warm water 40-50 bromide hydrobromide precipitates as acetone and ether melts of 5,6-dimethoxy-8-aminoquinoline, and sufficient disodium phosphate-ritric acid buifer to bring the solution to a pH of 4.8; is held to degrees of 45 C; with stirring, for a period of 12-14 hours. Th temperature is then increased to 60 C. for 1 hour, then to 70 C. for 1 hour, and finally to 95:100

'is distilled,

C. under partial vacuum, 0.5 mm. in

the desired 5,6-dimethoxy-8-(1'-methyl-4'-isopropylaminobutylamino)-quinoline, which boils at 190495 C. at 0.3 mm. pressure. It forms an oxalate melting at 1938-141 C. a

' Example 2 5,6 dimethoxy-S- 1 '-methyl-5isopropylaminopentylamino) -quinoline represented by the following formula H3O o HN-OH(CH2)4:NH(|3HOH;

H3 V cm may be prepared by the procedure of Example 1, save that instead of i-methyl-4-isopropylaminobutyl bromide hydrobromide, the hydrobromide of l-methyl-5-isopropylaminopentyi bromide is This propylamino) hexano1-5. converted to 1-methyl-5-isopropylaminopentyl bromide hydrobromide by treating a cold benzene -methyl-5-isopropy1aminopentyl a solid, mixture of.

and after recrystallization from a at 142=143A as nitrogen. This yields Example 3 5,6-dimethoXy-8(P-ethylamino)-quinoline represented formula -ethylaminobutylby the following moo \N a e HI T (CHz)aCH 'NHC2H5 V (12H? may be prepared by the procedure of Example 1, save that instead of the hydrobromide there used, the hydrobromide of 4-ethyl-4-ethylaminobutyl bromide is used. This latter compound is described in our copending application Serial No. 660,413, filed April 8, 1946, and in the Elderfield et al. publication, J. Am. Chem. 800., 68, 1579 (1946). i

7 Example 4 1 5,6 dimethoxy-8- l' -methyl l -ethylaminobutylamino)-qu1noline may be prepared by the latter compound is disclosed by Elderfield and Brody, supra. 7

Example 6 5,6 dimethoxy-8(1f-methyl-4'-isobutylaminobutylamino) -quino1ine may be prepared by the procedure of Example 1, save that instead of the hydrobromide there I Example 7 M n v 5,6 dimethoxy-a-(1'-methyl-4'-tert.butylaminobutylamino)-qumcline may be th and Brody,'supra.

V 4 Ewample 8 v v .Anyjcf the preceding' examples may be repeated, save that hydrobromides of other alkylaminoalkyl bromides of Formula 2 are used, to produce other 5,6-dimethoxy-8 substituted quinolines of Formula 1, and their salts. V

We claim as ourinventionfl i 7 1 ,1. The new antimalarials of the ciass consisting of 5,6-dimethoxy-8-substituted quinolines represented by. the following formula in which R is a polymethylene chain having from 4 to carbon atoms and substituted with one of the radicals selected from the group consisting of methyl and ethyl, and R1 is an alkyl radical having from 1 to 6 carbon atoms, and their salts.

2. The new antimalarials of the class consisting of 5,6-dimethoXy-8-substituted quinolines represented by the following formula in which R1 is an alkyl radical having from 1 to 6 carbon atoms, and their salts.

3. The new antimalarials of the class consist---- ing of 5,6-dimethoxy-B-substituted quinolines represented by the following formula HN(OHa) OH--NHR1 02H! in which R1 is an alkyl radical having from 1 to 6 carbon atoms, and their salts.

4. The new antimalarials ing of 5,6dimethoxy-S-substituted quinclines represented by the following formula N HAT-CH-{CHsDr-NH-R,

in which R1 is an alkyl radical having from 1 to 6 carbon atoms, and their salts.

5. The process of preparing the new antimalarials having the formula HNRNH-R1 defined in claim 1 which comprises condensing 5,6-dimethoxy-8-aminoquinoline and the hydrobromide of an alkylaminoalkyl bromide of the following formula of the class consistin which R and R1 have the same meaning as in claim 1.

6. The process of preparing the new antimalarials having the formula Eye 0-- HN-RNHR1 defined in claim 1 which comprises condensing 5,6-dimethoxy-8-aminoquinoline and the hydrobromide of an alkylaminoalkyl bromide of the following formula in which R and R1 have the same meaning as in claim 1, in aqueous solution buffered to a pH of about 4.8.

7. The process of preparing the new antimalariais having the formula HN-R-NHR1 defined in claim 1 which comprise-s mixing 5,6- dimethoxy-S-aminoquinoline and the hydrobromide of an alkylaminoalkyl bromide of the following formula in which R and R1 have the same meaning as in claim 1, in aqueous solution buffered to a pH of about 4.8, maintaining the said mixture with-- in a few degrees of 45 C. for a period of about 12 to 14 hours, then progressively raising the temperature to about C. and maintaining it at that temperature for several hours.

ROBERT C. ELDERFIELD. JAMES D. HEAD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,938,047 Schonhofer et al. Dec. 5, 1933 FOREIGN PATENTS Number Country Date 536,447 Germany Oct. 23, 1931 OTHER REFERENCES Shriner and Upson, Synthetic Antimalarials (published in Bloomington, Indiana, 1941), page 9. (Copy in Division 59.) 

